Rear bumper for a motor vehicle



FIG. 1 is a perspective view of a rear bumper for a motor vehicle of our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right-side view thereof; and,

FIG. 6 is a left-side view thereof. 

The ornamental design for a rear bumper for a motor vehicle, as shown and described. 